This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2000-112282, filed Apr. 13, 2000, the entire contents of which are incorporated herein by reference.
The present invention relates to a suspension for a disc drive disposed in an information processing apparatus such as a personal computer.
In a disc drive provided with a rotary magnetic disc or a magneto optical disc, a magnetic head is used to record or read data with respect to a disc recording surface. This magnetic head includes a slider disposed opposite to the disc recording surface, and a transducer disposed in a slider. When the disc rotates at a high speed, the slider slightly lifts above the disc, and an air bearing is therefore formed between the disc and the slider.
In an example shown by FIG. 22, a suspension for disc drive for holding the magnetic head includes a load beam 1 of a precise plate spring, a flexure 2 of a thin plate spring fixed to a tip end of the load beam 1, and a base plate 3 fixed to a base of the load beam 1. A slider 4 is attached to a tip end of the flexure 2.
In an assembling process of such suspension, it is remarkably important to accurately position the load beam 1 and flexure 2. Positions of the load beam 1 and flexure 2 which have to be originally in an accurate positional relation deviate, and a position of the slider 4 attached later deviates.
For example, as shown in FIG. 22, it is assumed that a position deviation xcex94C is produced between a center line C1 of the load beam 1 and a center line C2 of the flexure 2. In this case, as shown in FIG. 23, distances D1, D2 between a center C3 of the slider 4 and opposite sides of the flexure 2 differ from each other. As a result, a dynamic balance of spring pressures P1, P2 on opposite sides of the flexure 2 is destroyed, and the slider 4 cannot be stabilized and cannot be lifted above the disc. In this case, data is unstably written or read with respect to the disc.
To mutually position the load beam 1 and flexure 2, a positioning jig 10 as shown in FIG. 24 and 25 has been proposed. Two reference holes 11, 12 are formed in the load beam 1. Two reference holes 13, 14 are also formed in the flexure 2. One common positioning pin 15 is inserted into the reference holes 11, 13 positioned on the left side in FIG. 25. Two positioning pins 16, 17 independent of each other are inserted into the reference holes 12, 14 positioned on the right side. When the pins 16, 17 are pulled in directions shown by arrows F1, F2 in FIG. 24 by urging means 18 such as a spring or actuator, the load beam 1 and flexure 2 are positioned. These positioning pins 15, 16, 17 are disposed on a common jig main body 19.
Since the urging means 18 is disposed in the conventional positioning jig 10,, a structure is remarkably complicated. Additionally, in the positioning jig 10, the positions of the pins 15, 16, 17 are required to be managed with high precision. Therefore, when a plurality of jigs 10 are manufactured, it is difficult to manufacture the same jig. When the number of jigs 10 increases, a dispersion of the jig 10 tends to increase. As a result, positioning precision of the load beam 1 and flexure 2 is deteriorated. Moreover, since the constitution of the jig 10 is complicated, it needs to be constantly monitored/checked whether or not the urging means 18 accurately operates, and this requires remarkably much troublesome and time.
Additionally, the conventional positioning jig 10 requires three pins 15, 16, 17. One of these pins is the pin 15 common to the load beam 1 and flexure 2. For the remaining two pins 16, 17, one is the pin 16 for pulling the load beam 1, and the other is the pin 17 for pulling the flexure 2. Since two pins 16, 17 independent of each other are used, the positions of the pins 16, 17 sometimes deviate from each other in an Y-axis direction in FIG. 24. This also deteriorates the position precision of the load beam 1 with the flexure 2.
Therefore, an object of the present invention is to provide a suspension for a disc drive in which a load beam and flexure can accurately be positioned, and a constitution of a positioning jig can be simplified.
According to a first aspect of the present invention, there is provided a suspension for a disc drive having a load beam, and a flexure fixed at a predetermined position of the load beam and provided with a magnetic head section, the suspension for the disc drive comprising:
a first reference hole which is formed in the vicinity of one end of the load beam and into which a first positioning pin is inserted; a first spring portion which is formed in a part of the load beam including an inner peripheral edge of the first reference hole and which abuts on the first positioning pin with elastic deformation to urge the load beam in an axial direction thereof; a second reference hole which is formed in the vicinity of the other end of the load beam and into which a second positioning pin is inserted; a second spring portion which is formed in a part of the load beam including an inner peripheral edge of the second reference hole and which abuts on the second positioning pin with the elastic deformation to urge the load beam in the axial direction thereof; a third reference hole which is formed in the vicinity of one end of the flexure and into which the first positioning pin is inserted; a third spring portion which is formed in a part of the flexure including an inner peripheral edge of the third reference hole and which abuts on the first positioning pin with elastic deformation to urge the flexure in an axial direction thereof; a fourth reference hole which is formed in the vicinity of the other end of the flexure and into which the second positioning pin is inserted; and a fourth spring portion which is formed in a part of the flexure including an inner peripheral edge of the fourth reference hole and which abuts on the second positioning pin with the elastic deformation to urge the flexure in the axial direction thereof.
In the suspension of the present invention, the first positioning pin is inserted into the first and third reference holes, and the second positioning pin is inserted into the second and fourth reference holes. When the first and third spring portions abut on the first positioning pin, the load beam and flexure are pulled in the axial direction, using the first positioning pin as a support. Moreover, since the second and fourth spring portions abut on the second positioning pin, the load beam and flexure are pulled in the axial direction, using the second positioning pin as the support. The load beam and flexure are positioned by two positioning pins in this manner.
According to the present invention, the respective spring portions formed on the load beam and flexure are utilized to pull the load beam and flexure in the axial direction thereof. Therefore, the positioning jig for positioning the load beam and flexure may be provided with two positioning pins. Additionally, since it is unnecessary to dispose the urging means on the positioning jig, a constitution of the positioning jig is simplified. Moreover, the positioning jig can accurately position the load beam and flexure without being influenced by positioning pin precision. The respective spring portions of the load beam and flexure are used only once in principle during positioning of one suspension. Therefore, spring fatigue or change with elapse of time does not have to be considered, monitoring check necessary for the urging means of a conventional positioning jig is unnecessary, and high precision is always obtained.
In the present invention, the first and second spring portions are, for example, elastically deformable portions between a pair of slits formed along the axial direction in the load beam, and the third and fourth spring portions are elastically deformable portions between a pair of slits formed along the axial direction in the flexure. According to the present invention, the spring portion can be formed in accordance with a length of the slit. In this case, when the spring portion is lengthened, a spring constant is lowered and the spring portion is easily deflected. The spring constant can be adjusted if necessary.
In the present invention, a guide surface for aligning center lines of the load beam and flexure with respect to the positioning pin may be formed on at least one of a tip end of the spring portion which abuts on the first positioning pin, and the inner peripheral edge of the reference hole. According to the present invention, when the spring portion is pressed onto the first positioning pin, the load beam and flexure can mutually be centered by the guide surface.
In the present invention, a guide surface for aligning center lines of the load beam and flexure with respect to the positioning pin may be formed on at least one of a tip end of the spring portion which abuts on the second positioning pin, and the inner peripheral edge of the reference hole. According to the present invention, when the spring portion is pressed onto the second positioning pin, the load beam and flexure can mutually be centered by the guide surface.
In the present invention, the respective tip ends of the third and fourth spring portions formed on the flexure may project to the inside of the reference hole from the respective tip ends of the first and second spring portions formed on the load beam. According to the present invention, even when the positioning pin is inserted into the respective reference holes and the first and second spring portions are deflected, the tip ends of the third and fourth spring portions are allowed to abut on the positioning pin.
In the present invention, in order to lower spring constants of the respective spring portions, a through hole or a portion with a reduced thickness may be formed in at least a part of the spring portion. According to the present invention, the spring portion can easily be deflected as occasion demands by lowering the spring constant of the spring portion.
According to another aspect of the present invention, there is provided a suspension for a disc drive, comprising: a first reference hole which is formed in the vicinity of one end of the load beam and into which a first positioning pin is inserted; a second reference hole which is formed in the vicinity of the other end of the load beam and into which a second positioning pin kept at a constant distance from the first positioning pin is inserted; a load beam spring portion which is formed in a part of the load beam including an inner peripheral edge of the first or second reference hole and which abuts on the first or second positioning pin with elastic deformation to urge the load beam in an axial direction thereof; a third reference hole which is formed in the vicinity of one end of the flexure and into which the first positioning pin is inserted; a fourth reference hole which is formed in the vicinity of the other end of the flexure and into which the second positioning pin is inserted; and a flexure spring portion which is formed in a part of the flexure including an inner peripheral edge of the third or fourth reference hole and which abuts on the first or second positioning pin with the elastic deformation to urge the flexure in an axial direction thereof.
In the suspension of the present invention, during positioning of the load beam and flexure, a positioning jig for keeping a distance (shortest distance) between the first positioning pin and the second positioning pin to be constant is used. The first positioning pin is inserted into the first and third reference holes, and the second positioning pin is inserted into the second and fourth reference holes. The load beam and flexure are pulled in the axial direction, using the one positioning pin as a support by the spring portions formed on the load beam and flexure, and positioned by the first and second positioning pins. According to the present invention, since the spring portion may be formed on one portion of the load beam and the flexure, shapes of the load beam and flexure are further simplified.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.